Updated · how we check
Compress an image to 5 KB
To get an image under 5 KB, PixelFit aims at 5,000 bytes or less, so forms counting 1 KB as 1000 or 1024 bytes both accept it. Estimated from our measured encodes, that is about 147 × 110 pixels for a 4:3 photo at quality 75, or 115 × 143 for a portrait.
Under 5 KB
JPG · under 5 KB (at most 5,000 bytes) · original pixel size · white background
PixelFit aims at 5,000 bytes or less, so the file passes whether the form counts 1 KB as 1,000 or 1,024 bytes.
Fit, background and padding white background
Saving presets is part of Pro.
The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.
The batch kit (one ZIP for up to 500 photos, several photos merged into one PDF) is part of Pro.
What 5 KB means in bytes
5 KB is 5,120 bytes when 1 KB = 1024 bytes (5 × 1024) and 5,000 bytes when a server counts 1 KB = 1000 bytes. The 120-byte gap matters only near the limit. PixelFit aims at 5,000 bytes or less and prints the exact byte count, so you can compare it with the form.
5 KB is 0.005 MB; 2,048 such files fit in 10 MB. Uncompressed, the 147 × 110 photo that fits here would need 47.4 KB of raw pixels, so JPEG at quality 75 packs it about 10 to 1.
Largest pixel size that fits 5 KB
The biggest image of each kind, in its own aspect ratio, that stays at or below 5,000 bytes.
| Image | JPG q60 | JPG q75 | JPG q90 | WebP q75 |
|---|---|---|---|---|
| Head-and-shoulders portrait | 136 × 169 | 115 × 143 | 88 × 109 | 133 × 166 |
| Outdoor landscape (12 MP phone photo) | 174 × 130 | 147 × 110 | 113 × 84 | 161 × 120 |
| Scanned typed document page | 172 × 216 | 148 × 185 | 113 × 141 | 171 × 214 |
| Handwritten letter with signature | 294 × 241 | 242 × 198 | 175 × 143 | 355 × 291 |
| Flat-colour graphic (flag) | 297 × 207 | 245 × 171 | 175 × 122 | 362 × 253 |
A 12 MP phone photo at 5 KB
Our 12 MP landscape sample (4032 × 3024) is about 4.15 MB at quality 90, 871 times the 5 KB budget; even quality 30 leaves 1.26 MB (extrapolated from encodes up to 3,000 px). So the pixels must go down too.
At about quality 75 it fits 5 KB near 147 × 110 (0.02 MP, 0.13 % of the original pixels). Quality 60 allows 174 × 130; quality 90 needs 113 × 84.
JPEG quality for fixed pixel sizes under 5 KB
When a form fixes the pixels, only quality can move. Highest quality (of 100) that keeps each size at or under 5,000 bytes:
| Pixel size | Measured on | JPG | WebP |
|---|---|---|---|
| 140 × 60 (small signature box) | handwritten page | quality 95+ (2.7 KB) | quality 95+ (1.8 KB) |
| 300 × 120 (signature strip) | handwritten page | quality 82 (4.8 KB) | quality 91 (4.6 KB) |
| 200 × 230 (small ID photo) | portrait photo | no: fewer pixels needed | quality 35 (4.8 KB) |
| 413 × 531 (35 × 45 mm at 300 DPI) | portrait photo | no: fewer pixels needed | no: fewer pixels needed |
| 600 × 600 (2 × 2 inch at 300 DPI) | portrait photo | no: fewer pixels needed | no: fewer pixels needed |
| 800 × 600 (4:3 web photo) | landscape photo | no: fewer pixels needed | no: fewer pixels needed |
Measured JPEG files either side of 5 KB
Real encodes from our test set at quality 75: the largest file that stays under 5,000 bytes and the smallest that goes over.
| Image | Largest under 5 KB | Smallest over 5 KB |
|---|---|---|
| Head-and-shoulders portrait | 80 × 100: 2,858 B | 120 × 150: 5,309 B |
| Outdoor landscape (12 MP phone photo) | 100 × 75: 2,585 B | 150 × 113: 5,138 B |
| Scanned typed document page | 119 × 150: 3,269 B | 159 × 200: 5,724 B |
| Handwritten letter with signature | 200 × 164: 3,553 B | 250 × 206: 5,311 B |
| Flat-colour graphic (flag) | 200 × 140: 3,906 B | 250 × 175: 5,116 B |
JPG, WebP or PNG at 5 KB
At quality 75, WebP holds 161 × 120 of the landscape photo in 5 KB, JPG 147 × 110: 19 % more pixels. Portrait gain: 34 %. Typed page gain: 34 %. A moderate gain at 5 KB. Many portals accept only JPG/JPEG, so this page starts in JPG.
A full-colour PNG is lossless, so its size follows the content. In 5 KB it holds a flat graphic of 155 × 108 pixels but a photo of only 53 × 39 (extrapolated), against 147 × 110 as a quality-75 JPG. Reducing a PNG to a palette of up to 256 colours (PixelFit does this when a PNG must shrink) helps graphics far more than photos.
Signatures and thumbnails under 5 KB
In our form dataset, 14 photo or signature limits are 20 KB or less: 12 for signatures, 2 for photos. Measured for 5 KB:
- A handwritten page fits at 242 × 198 at quality 75, so a cropped signature strip has room to spare.
- A typed page fits at 172 × 216 at quality 60: crop to the lines the form needs.
- A portrait fits at 115 × 143 at quality 75, a stamp-size photo.
- Cropping empty paper first leaves more of the 5,000 bytes for the strokes or the face.
How to compress an image to 5 KB
-
Open the tool above
It is preset to 5 KB (5,000 bytes or less), JPG output.
-
Add your image
Drop, paste or pick it; a PNG, WebP or (where the browser opens it) HEIC file becomes a JPG under 5 KB.
-
Pixel size: only if asked
On auto, a typical photo stops near 147 × 110 at about quality 75.
-
Download and check
name-5kb.jpg comes with its byte count, pixels and quality.
Sources
- Measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026.
- Sample images, Wikimedia Commons, checked 31 October 2026: landscape (CC0 1.0) commons.wikimedia.org/w/index.php?curid=154070378; portrait commons.wikimedia.org/w/index.php?curid=23956389; typed page commons.wikimedia.org/w/index.php?curid=194775753; handwritten letter commons.wikimedia.org/w/index.php?curid=90423615; flag commons.wikimedia.org/w/index.php?curid=361734 (public domain).
- Binary prefixes, NIST, checked 31 October 2026: physics.nist.gov/cuu/Units/binary.html
Frequently asked questions
How do I compress an image to 5 KB?
Drop it into the tool here, preset to 5 KB. It searches JPEG quality (at most 8 encodes per pixel size), then scales pixels down if needed, until the file is 5,000 bytes or less. A 4:3 photo typically lands near 147 × 110 at about quality 75.
How do I compress an image to less than 5 KB without losing quality?
Give up pixels before quality: at quality 75, 5 KB holds 147 × 110 of a photo and 115 × 143 of a portrait; quality 90 at 147 × 110 costs 58 % more bytes.
Is 5 KB 5,000 or 5,120 bytes?
Both readings exist: 5,120 bytes (1 KB = 1024) or 5,000 bytes (1 KB = 1000). 5,000 bytes or less passes both.
Can I compress a PNG to 5 KB?
Yes, but a full-colour PNG photo stays big: about 53 × 39 (extrapolated) pixels in 5 KB, versus 155 × 108 for a flat graphic. As a JPG the photo reaches 147 × 110.
Why does my signature look blurry at 5 KB?
Usually the scan is huge and gets scaled down hard. Crop tightly first: a handwritten page fits 5 KB at 242 × 198 at quality 75.
Related
Nearby file sizes
- Compress to 10 KB photo ≈ 221 × 165
- Compress to 12 KB photo ≈ 243 × 182
- Compress to 15 KB photo ≈ 273 × 204
More ways to hit 5 KB
- Image resizer with KB target Any size, pixels and format
Pixel sizes that fit 5 KB
- 128×128 app icon about 4.9 KB as a quality-75 JPG
- 320×50 banner about 4.8 KB as a quality-75 JPG
- 100×100 square about 3.2 KB as a quality-75 JPG
- 96×96 icon about 3 KB as a quality-75 JPG